1 files changed, 118 insertions, 31 deletions

diff --git a/libjava/classpath/java/awt/font/TextMeasurer.java b/libjava/classpath/java/awt/font/TextMeasurer.java
index 18c286c57c1..00cab8a878d 100644
--- a/libjava/classpath/java/awt/font/TextMeasurer.java
+++ b/libjava/classpath/java/awt/font/TextMeasurer.java
@@ -1,5 +1,5 @@
 /* TextMeasurer.java
-   Copyright (C) 2003 Free Software Foundation, Inc.
+   Copyright (C) 2006 Free Software Foundation, Inc.
 
 This file is part of GNU Classpath.
 
@@ -38,67 +38,154 @@ exception statement from your version. */
 
 package java.awt.font;
 
-import gnu.classpath.NotImplementedException;
-
 import java.text.AttributedCharacterIterator;
+import java.text.AttributedString;
+import java.awt.Shape;
 
 /**
- * @author Michael Koch
+ * TextMeasurer is a small utility class for measuring the length of laid-out
+ * text objects. 
+ *
+ * @author Sven de Marothy
  * @since 1.3
  */
 public final class TextMeasurer implements Cloneable
 {
-  private AttributedCharacterIterator ci;
+  private AttributedCharacterIterator text;
   private FontRenderContext frc;
-  
+  private TextLayout totalLayout;
+  private int numChars;
+
+  /**
+   * Creates a TextMeasurer from a given text in the form of an
+   * <code>AttributedCharacterIterator</code> and a 
+   * <code>FontRenderContext</code>.
+   */  
   public TextMeasurer (AttributedCharacterIterator text, FontRenderContext frc)
   {
-    this.ci = text;
+    this.text = text;
     this.frc = frc;
+    totalLayout = new TextLayout( text, frc );
+    numChars = totalLayout.getCharacterCount();
   }
 
+  /**
+   * Clones the TextMeasurer object
+   */
   protected Object clone ()
   {
-    try
-      {
-        return super.clone ();
-      }
-    catch (CloneNotSupportedException e)
-      {
-        // This may never occur
-        throw new InternalError ();
-      }
+    return new TextMeasurer( text, frc );
   }
 
+  /**
+   * Update the text if a character is deleted at the position deletePos
+   * @param newParagraph - the updated paragraph.
+   * @param deletePos - the deletion position
+   */
   public void deleteChar (AttributedCharacterIterator newParagraph,
                           int deletePos)
-    throws NotImplementedException
   {
-    throw new Error ("not implemented");
+    totalLayout = new TextLayout(newParagraph, frc);
+    if( deletePos < 0 || deletePos > totalLayout.getCharacterCount() )
+      throw new NullPointerException("Invalid deletePos:"+deletePos);
+    numChars = totalLayout.getCharacterCount();
+    text = newParagraph;
+  }
+
+  /**
+   * Update the text if a character is inserted at the position insertPos
+   * @param newParagraph - the updated paragraph.
+   * @param insertPos - the insertion position
+   */
+  public void insertChar (AttributedCharacterIterator newParagraph,
+                          int insertPos)
+  {
+    totalLayout = new TextLayout(newParagraph, frc);
+    if( insertPos < 0 || insertPos > totalLayout.getCharacterCount() )
+      throw new NullPointerException("Invalid insertPos:"+insertPos);
+    numChars = totalLayout.getCharacterCount();
+    text = newParagraph;
   }
 
+  /***
+   * Returns the total advance between two positions in the paragraph.
+   * Characters from start to limit-1 (inclusive) are included in this count.
+   *
+   * @param start - the starting character index.
+   * @param limit - the limiting index.
+   */
   public float getAdvanceBetween (int start, int limit)
-    throws NotImplementedException
   {
-    throw new Error ("not implemented");
+    Shape s = totalLayout.getLogicalHighlightShape( start, limit );
+    return (float)s.getBounds2D().getWidth();
   }
 
+  /**
+   * Returns a <code>TextLayout</code> object corresponding to the characters
+   * from text to limit.
+   * @param start - the starting character index.
+   * @param limit - the limiting index.
+   */
   public TextLayout getLayout (int start, int limit)
-    throws NotImplementedException
   {
-    throw new Error ("not implemented");
+    if( start >= limit )
+      throw new IllegalArgumentException("Start position must be < limit.");
+    return new TextLayout( totalLayout, start, limit );
   }
 
+  /**
+   * Returns the line-break index from a given starting index and a maximum
+   * advance. The index returned is the first character outside the given
+   * advance (or the limit of the string, if all remaining characters fit.)
+   *
+   * @param start - the starting index.
+   * @param maxAdvance - the maximum advance allowed.
+   * @return the index of the first character beyond maxAdvance, or the 
+   * index of the last character + 1.
+   */
   public int getLineBreakIndex (int start, float maxAdvance)
-    throws NotImplementedException
-  {
-    throw new Error ("not implemented");
-  }
+  {   
+    if( start < 0 )
+      throw new IllegalArgumentException("Start parameter must be > 0.");
+
+    double remainingLength = getAdvanceBetween( start, numChars );
+    
+    int guessOffset = (int)( ( (double)maxAdvance / (double)remainingLength)
+			     * ( (double)numChars - (double)start ) );
+    guessOffset += start;
+    if( guessOffset > numChars )
+      guessOffset = numChars;
+    
+    double guessLength = getAdvanceBetween( start, guessOffset );
+    boolean makeSmaller = ( guessLength > maxAdvance );
+    int inc = makeSmaller ? -1 : 1;
+    boolean keepGoing = true;
+
+    do
+      {
+	guessOffset = guessOffset + inc;
+	if( guessOffset <= start || guessOffset > numChars )
+	  {
+	    keepGoing = false;
+	  }
+	else
+	  {
+	    guessLength = getAdvanceBetween( start, guessOffset );
+	    if( makeSmaller && ( guessLength <= maxAdvance) )	  
+	      keepGoing = false;
+	    if( !makeSmaller && ( guessLength >= maxAdvance) )
+	      keepGoing = false;
+	  }
+      }
+    while( keepGoing );
 
-  public void insertChar (AttributedCharacterIterator newParagraph,
-                          int insertPos)
-    throws NotImplementedException
-  {
-    throw new Error ("not implemented");
+    // Return first index that doesn't fit.
+    if( !makeSmaller )
+      guessOffset--;
+
+    if( guessOffset > numChars )
+      return numChars;
+
+    return guessOffset;
   }
 }